Invar, Kovar and soft-magnetic nickel–iron grades for instruments, seals and electronic packaging.
Controlled-expansion and soft-magnetic alloys are bought for a physical property rather than for strength: a coefficient of thermal expansion that matches glass or ceramic, or a permeability that stays stable in a magnetic circuit.
We supply bar, strip, sheet and machined parts, with expansion or magnetic measurements reported where the application requires them.
| Grade | UNS | Typical service |
|---|---|---|
| 4J36 (Invar 36) | FeNi36 / 1.3912 | Ultra-low expansion; instrument frames, resonators, bimetal passive layers. |
| 4J42 | FeNi42 | Expansion matched to hard and soft glass; glass-to-metal seals. |
| 4J29 (Kovar) | FeNi29Co17 / 1.3981 | Matched seals to borosilicate glass; vacuum tubes and feedthroughs. |
| 4J32 (Super Invar) | FeNi32Co | Lower expansion than 4J36 for dimensionally critical optics and metrology. |
| 1J79 / 1J85 | FeNiMo | High initial permeability; pulse transformers, magnetic amplifiers, shielding. |
| 1J38 / 1J50 | FeNi | High permeability with higher saturation; magnetic shunt and instrument magnets. |
Quotes within one business day. Send grade, size, pressure class, face type and quantity — a drawing works better than a description.
